Species

An introduction to species

There are two broad divisions for wood species – softwoods, and hardwoods. Softwoods comes from cone-bearing trees, which are described as coniferous, while hardwoods comes from broad leaved trees. While useful as broad categories, it is important to know the specific species and country of origin to understand how a timber is likely to perform.

Borisov sawmill forests nursery farm

Softwoods

Softwood timber is obtained from conifers – trees with needle-like leaves, usually bearing cones. Softwoods are the most commonly-used timber because they offer good value and are readily available from sustainably-managed forests. They are less dense and easier to work with than most hardwoods.

 

Of the 650 species of softwoods throughout the world, around 50 are in commercial use, with the most common being European Redwood and Whitewood (pine and spruce). Most softwood used in the UK comes from Sweden, the UK, Finland, Latvia, Germany and Russia.

 

The properties of softwoods

 

While softwoods are generally regarded to have lower density and less resilience than hardwoods, this varies significantly be species. With treatment, softwoods may last decades in even the most adverse conditions.

 

One of the greatest advantages of softwoods is how quickly they grow. In as few as 35 years, a Sitka spruce growing might grow as tall as 23 m depending on the conditions of it’s environment. Because they grow so quickly, they absorb vasts amounts of carbon dioxide from the atmosphere.

 

The advantage of harvesting trees once they’ve grown to their peak heights, is it clears the way for new trees to absorb and store more carbon dioxide, with well managed forests the most effective way we currently have to absorb and store carbon.

 

Where in the UK will I find softwood trees being used in construction

 

Just about in all areas of construction you will find softwood timber being used. One of the most important is timber frame houses, which are growing in popularity in the UK.

 

However, the uses of softwood timber are endless and you will find them used throughout the house, whether in stairs, bannisters, or floors. Modern science means you can even build tall buildings with softwood timber.

Hardwoods

Hardwoods are mainly broadleaf, deciduous trees, shedding their leaves in winter, although some hardwoods are evergreen. There are two groups, temperate and tropical, accounting for some 20,000 different commercial species.

 

Although generally more durable and stronger than softwood, they must be used in the correct way and specified according to the environmental conditions which they will face – with some requiring treatement.

 

Unlike softwoods, which can grow extraordinarily quickly – hardwoods generally grow at a far slower rate, so it is particularly important that they are managed through sustainable forestry practices.

 

The properties of hardwoods

 

Hardwoods have a denser structure, with a well known example from the UK being Oak. However, they can be found all over the world, and often are split into two camps, being temperate hardwood and tropical hardwood.

 

While Oak is a well known UK example of a hardwood, there are a huge range of hardwoods which are commercially available, and sustainably sourced hardwoods are an important market for promoting better global forestry practices.

 

Where in the UK will I find hardwoods being used

 

While hardwoods may not have the heightened profile they once did, their beauty and strength means they continue to be prized. As the generally carry a higher price, they are less likely to be found in the structural elements.

 

However, the strength and resilience of hardwoods to weather or heavy use make them great for flooring or windows. When cared for they will outlast many other materials, which also makes them a great choice for furniture.

 

Where does hardwood in the UK come from

 

While they can be found in all areas of the world, including Europe, North America, South America, Asia, Australia and New Zealand, generally hardwoods are understood to be either tropical or temperate.

 

Temperate hardwoods, such as oak, birch or beech, most often come from Europe or North America, and given their long history of use in the UK, are often a popular choice as they provide a very traditional aesthetic.

 

Tropical hardwoods are sourced from Africa, Asia and South America. There are thousands of tropical species available, and they provide an essential income to many otherwise impoverished communities.

 

Because of how long hardwood timber tends to take to grow, it is important to take steps to ensure that this timber comes from a sustainable source. Read our timber trade topic on Sourcing Sustainable Timber for more info on how to ensure your timber is sustainable.

Tropical Hardwoods

Found in tropical areas such as Central and South America, West and Central Africa and South East Asia.

 

Illegal trade in tropical hardwoods has been largely responsible for deforestation. Care should be taken to ensure you are supplied with timber from legal and sustainable sources. See our Wood Campus CPD module on Procuring Sustainable Timber.

 

Temperate hardwood comes from forests across the eastern United States, Canada, Europe, China, Japan, and parts of Russia. Tropical hardwood comes from continents surrounding the Equator; mainly Central and West Africa, Southeast Asia and South America.

 

Tropical hardwood comes from continents surrounding the Equator; mainly Central and West Africa, Southeast Asia and South America.

 

Tropical hardwood’s qualities include strength and resistance to abrasion or impact. Fire resistance tends to be better in hardwood products due to its higher density.

 

Both temperate and tropical hardwoods are popular in UK construction due to their natural durability.

 

Oak and sweet chestnut are ideal temperate hardwoods for external construction. They’re commonly used in timber frame buildings.